【HDU】3498 whosyourdaddy

#include<cstdio>
#include<cstring>
#include<algorithm>
#define MAXN 10000
#define MAXM 60
#define INF 0x7FFFFFFF
using namespace std;
bool G[MAXM][MAXM];
int R[MAXN], L[MAXN], U[MAXN], D[MAXN];
int size, ans, C[MAXN], S[MAXN], H[MAXN];
bool vis[MAXM];
void Init(int n)
{
    int i;
    memset(G, false, sizeof(G));
    for (i = 0; i <= n; i++)
    {
        R[i] = i + 1;
        L[i + 1] = i;
        U[i] = D[i] = i;
        S[i] = 0;
        H[i] = -1;
    }
    R[n] = 0;
    size = n + 1;
}
void Link(int r, int c)
{
    U[size] = c;
    D[size] = D[c];
    U[D[c]] = size;
    D[c] = size;
    if (H[r] < 0)
        H[r] = L[size] = R[size] = size;
    else
    {
        L[size] = H[r];
        R[size] = R[H[r]];
        L[R[H[r]]] = size;
        R[H[r]] = size;
    }
    S[c]++;
    C[size++] = c;
}
void Remove(int c)
{
    int i;
    for (i = D[c]; i != c; i = D[i])
    {
        L[R[i]] = L[i];
        R[L[i]] = R[i];
    }
}
void Resume(int c)
{
    int i;
    for (i = D[c]; i != c; i = D[i])
        L[R[i]] = R[L[i]] = i;
}
int A()
{
    int i, j, k, res;
    memset(vis, false, sizeof(vis));
    for (res = 0, i = R[0]; i; i = R[i])
    {
        if (!vis[i])
        {
            res++;
            for (j = D[i]; j != i; j = D[j])
            {
                for (k = R[j]; k != j; k = R[k])
                    vis[C[k]] = true;
            }
        }
    }
    return res;
}
void Dance(int now)
{
    if (R[0] == 0)
        ans = min(ans, now);
    else if (now + A() < ans)
    {
        int i, j, temp, c;
        for (temp = INF,i = R[0]; i; i = R[i])
        {
            if (temp > S[i])
            {
                temp = S[i];
                c = i;
            }
        }
        for (i = D[c]; i != c; i = D[i])
        {
            Remove(i);
            for (j = R[i]; j != i; j = R[j])
                Remove(j);
            Dance(now + 1);
            for (j = L[i]; j != i; j = L[j])
                Resume(j);
            Resume(i);
        }
    }
}
int main()
{
    int n, m, u, v, i, j;
    while (~scanf("%d%d", &n, &m))
    {
        Init(n);
        while (m--)
        {
            scanf("%d%d", &u, &v);
            G[u][v] = G[v][u] = true;
        }
        for (i = 1; i <= n; i++)
        {
            G[i][i] = true;
            for (j = 1; j <= n; j++)
            {
                if (G[i][j])
                    Link(i, j);
            }
        }
        ans = INF;
        Dance(0);
        printf("%d\n", ans);
    }
    return 0;
}